火嘴的火焰缩火、回火是因为()。
A、配风量太大
B、配风量太小
C、瓦斯带油
D、瓦斯带水
参考答案:D
As the years passed, many occasions-birthdays, awards, graduations__________ with Dad's flowers. [ ]
A. are marked
B. were marked
C. have marked
D. had marked
以下哪种状态不会在小区对象上出现()
A.未激活
B.复位中
C.正常
D.闭塞